-XX:MaxPermSize with or without -XX:PermSize

Question

We\'ve run into a Java.lang.OutOfMemoryError: PermGen space error and looking at the tomcat JVM params, other than the -Xms and -Xmx

Answer 1

If you're doing some performance tuning it's often recommended to set both -XX:PermSize and -XX:MaxPermSize to the same value to increase JVM efficiency.

Here is some information:

1. Support for large page heap on x86 and amd64 platforms
2. Java Support for Large Memory Pages
3. Setting the Permanent Generation Size

You can also specify -XX:+CMSClassUnloadingEnabled to enable class unloading option if you are using CMS GC. It may help to decrease the probability of Java.lang.OutOfMemoryError: PermGen space